Disk brakes as mentioned above are known. The known brakes include electronic indicating devices to indicate the wear of the brake pad. In other disk brakes, the pad wear is measured using a tape measure or a ruler. Such a measurement is not sufficiently precise. What is also known is to measure the pad wear via a pin extending more or less from the caliper or the carrier of the brake, depending on the wear of the brake pad. Like the electronic indicating devices, these known solutions are laborious and complicated. Moreover, said pin can get jammed due to dirt making the measurement incorrect.
One embodiment of the present invention is directed to a caliper disk brake as mentioned above which is simpler, particularly with view to the indicating device, while providing a correct and precise wear indication.
According to one embodiment of the invention, the indicating device comprises a screw drive converting a linear movement of said pad with respect to said carrier into a rotational movement.
Advantageously, such a converting gear is a very simple part and easy to manufacture. The angle of the rotational movement gives sufficient information about the wear of the pad because said wear corresponds to a respective linear movement of (a back plate of) the pad with respect to the carrier. This is particularly true for the part of the linear movement resulting from wear compensation performed by a respective adjusting device integrated into the brake.
In one embodiment, said screw drive comprises a screw and a nut, said nut cooperating with said screw to rotate if linearly moved relative to said screw.
Said nut can be provided in various forms, particularly in the form of a sleeve.
According to one embodiment of the invention, the screw is held non-rotatable. Thereby, it is guaranteed that any rotation of the nut merely results from a linear movement of the pad and thereby of the screw relative to the carrier.
To enhance accuracy of the wear indication, to the invention may include a spring urging said nut to move away from said screw in response to wear of said brake pad. In other words, said spring is used to reliably hold said nut axially so that all the movement of the screw results from respective movement of the pad.
Said indicating device, in one embodiment, comprises a display means.
Said display means can be provided in various forms. In one embodiment, said display means comprises at least a first field related to a still tolerable wear and a second field related to a no more tolerable wear. With this embodiment of the invention, a user can take from the indicating device whether or not the wear of the pad is still tolerable or whether the pad must be replaced because the wear is no longer tolerable, based on which one of the first and second fields is displayed.
According to a further embodiment of the invention, what is provided is a protecting means protecting said display means from the environment, particularly from dirt, stones and the like.
Said protecting means may, in one embodiment, comprise a window through which a wear indicating information can be seen. Such a wear indicating information can, for example, be said first or said second field. If the first field can be seen through the window, a user knows that the pad is still ok. If, however, the second field can be seen through the window, the user knows that the pad is to be replaced. Instead of a window, what can be provided is a marker, said marker marking either the first or the second field, depending on the wear of the pad.
To simplify the overall construction, said protection means is, in one embodiment, held non-rotatable.
In addition to the above disk brake, the invention may also provide a wear indicating device for such a disk brake.